Telephone lines, which are carried by electrical conductors known as tip ring wire pairs, are generally aggregated at a particular point in a building prior to being distributed and connected to various types of telephone equipment, such as, for example, telephones, fax machines, modems etc. As the tip ring pairs generally enter the building as part of a multi-conductor cable, the aggregated tip ring wire pairs must first be broken out from the cable into individual wire pairs. This is normally accomplished in a wiring junction box known as, for example, a building entrance protector (BEP), or network interface unit (NIU). Within such devices the individual telephone line tip ring pairs are separated from the cable, individually connected to a connector block, and made available for further electrical connection and distribution. Usually there is a protector device inserted between the telephone and central office, or network side of the telephone line and the customer equipment or terminal side of the telephone line to protect the telephone and user, or other equipment connected to the telephone line, from hazardous overvoltages induced in the telephone network or in the cables passing between the telephone central office and the building within which the line is terminated.
In a typical arrangement, the telephone lines coming from the network are first wired to a protector field, which is an array of connectors for receiving the protector device, which is in turn hard wired to a first connector block which provides a first test point for testing the telephone line connections between the building and telephone central office. This first terminal block is hard wired to a multi pair connector, most typically a twenty-five pair connector of the RJ21 type, for further connection to an array of customer bridges which are also hard wired and connectorized via a mating RJ21 connector. The use of a customer bridge permits a subscriber to disconnect terminal equipment from a telephone line so that subscriber can isolate troubles on the line as originating in the telephone network, or on the terminal equipment side of the telephone line. An example of such an arrangement is shown in U.S. Pat. No. 5,363440, dated Nov. 8, 1994, the disclosure of which is incorporated herein by reference. U.S. Pat. No. 5,363,440, depicts a multi-layered network interface unit which results in size economies due to the fact that the customer bridge connector block is hingeably connected to the telephone network protector array field so that rather than placing these two arrays side by side they can be mounted in overlying relationship, resulting in a saving of space.
Typical connectors used in such applications are insulation displacement connectors (IDCs) of the type requiring a tool, such as the ubiquitous 66-type punch down connector, or tool-less IDC connectors such as the push cap SC-99 type connector sold by Lucent Technologies, Inc. or the mini-rocker type IDC sold by A.C. Egerton, LTD. Other connectors for use in telephony applications are described in U.S. Pat. No. 4,662,699, dated May 5, 1997, to Vachhani, et al., and U.S. Pat. No. 3,611,264, dated Oct. 5, 1971, to Ellis.
Additionally, there are known dual sided connector blocks for use in such junction boxes and/or distribution fields. These known terminal blocks consist of a first wiring connector on one side of the connector block, and a similar or different, electrically connected wiring connector on the other side of the block. Because the terminals in such blocks corresponding to either the tip or ring telephone wire on one side of the connector are reversed when the block is accessed from the other side, installers tend to make improper connections, thus, reversing the polarity of the telephone wires and causing the associated telephone equipment to malfunction. This greatly diminishes the flexibility and ease of use of such connector blocks.